Bit key lock guard



Jan. 3, 1967 w. HANKINS BIT KEY LOCK GUARD Filed Dec. 8, 1964 INVENTOR.Zia/M %//%/w///VJ United States Patent 3,295,344 BIT KEY LOCK GUARD LeonW. Hankins, R0. Box 224, 2646 W. Walnut St, Springfield, Mo. 65301 FiledDec. 8, 15 64, Ser. No. 416,766 3 Claims. (Cl. 7tl-43) This inventionrelates to a guard for bit key operated mortise or rim lock.

Heretofore, devices intended to prevent locks of the kind indicated frombeing operated and opened from the out sides of doors and the like, haveonly partially achieved their purposes since these devices failed topreclude operation of their bolts, by various means, such as theinsertion and manipulation of implements through their keyholes, and/orthe application of vibration or other shocks to the lock mechanisms.

The primary object of the present invention is the provision of areliable, efiicient, easily applied guard, which is adapted to besecured to a bit key and installed through a lock keyhole, from theinner side of the lock, in such a way that the bit of the key issecurely held in contact with the lock bolt and positively precludesopening operation of the bolt by any means applied from the outer sideof the lock.

Another object of the invention is the provision of a guard of thecharacter indicated above, which is of simple and uncomplexconstruction, so that it is adapted to be made and sold as aninexpensive and positive means of rendering ordinary locks, of theindicated types, burglarproof, and as means for preventing keys frombeing jarred loose from the locks, in open positions of the relateddoors, or the like.

In the drawings:

FIGURE 1 is a fragmentary edge elevation of a door equipped with amortise type, bit key operated lock, equipped with a guard of thepresent invention;

FIGURE 2 is an inside elevation of FIGURE 1;

FIGURE 3 is a vertical section taken on the line 3.3 of FIGURE 1,showing the guard retaining the keyoperated bolt of the lock in extendedor locking position;

FIGURE 4 is a fragmentary perspective view, showing the guard in processof installation relative to the lock and its key;

FIGURES 5 and 6 are perspective views of a left-hand guard,respectively.

Referring in detail to the drawings, D generally designates a doorhaving a free edge It), in which is flush mortised a conventional bitkey operated lock 12. Rotary handles 14 and 16 extend from the out sideand the inner side, respectively, of the door D, and are operativelysecured on related ends of a polygonal shaft 13, which operates a springlatch bolt 20.

The lock 12 comprises a vertically elongated case 22, containing, withinits upper part, the spring latch bolt 20, which extends through anopening 24, provided in the lock face 26.

Working through an opening 28, in the lock face 26, at a point spacedbelow the spring bolt 20, is a locking bolt 36 which is formed, in itslower edge, adjacent to its inner end, with a generally V-shaped notch32, having outer and inner cam edges 34 and 36, respectively. Alignedkeyholes 38 are provided in the side walls 40 of the lock case 22,beneath the locking bolt 30, in the region of the notch 32. Aconventional bit key 42 comprises a round shaft 44, having a stop collar46, adjacent its free end, and a lateral radial flat bit 48 located between the stop collar and the free end of the shaft, and an eye 49 onits outer end.

The bit 48 is adapted to be passed through a related keyhole 38, intothe locking bolt notch 32, for extending and retracting the locking bolt30. With reference ice to FIGURE 3, the key 42, after insertion in thelock, is adapted to be rotated, in a clockwise direction, so as to causethe bit 48 to bear against the inner cam edge 36, of the notch 32, forretracting the bolt 30; and to be rotated, in the opposite direction,for operatively engaging the outer cam edge 34, for extending the bolt30, to the position shown. Positive retention of the locking bolt 30, inthe extended locking position is obtained by a guard 50 of the presentinvention.

The guard 50 for use where the lock is at the left-hand edge of a door,as shown in FIGURE 5, comprises a longitudinally elongated fiat head 52,formed with two or more longitudinally spaced threaded holes 54, adaptedto receive the shank 56 of a wing-screw 58, having a relatively largediameter head 60. A longitudinally elongated, relatively narrow,substantially fiat guard arm 62 extends from the inner end of the flathead 52. The arm 62 is substantially narrower than the head 52 and isoffset to and is flush with one side edge 64 thereof.

As shown in FIGURES l, 2 and 4, the side edge 64 of the guard head 52is, in the installed position of the guard, the depressed edge of thehead 52, the arm 62 is twisted out of the plane of the head 60, into asubstantially perpendicular plane, disposed at an acute angle to theplane of the head. As shown in FIGURE 3, the arm 62 has upwardlyconverging opposed sides 66 and 68, respectively, and has a slightlyrounded lower edge 70, and a fiat upper edge 72. While the cross sectionof the arm 62, as shown in FIGURE 3, is less than the width of the slot74 of the keyhole 38, in which the outer end portion of the arm 62 islocated, in the installed position of the guard, the arm 62 must be wideenough to preclude substantial turning of the arm in the keyhole.

The guard 50 is installed by turning the key 42 in the lock so as toextend the bolt 36 to its locking position, as shown in FIGURE 3. Theguard arm 62 is then inserted in the slot '74 of the keyhole 38, beneaththe key, as far as the arm 62 will go. The eye 49 of the key 42 thenoverlies the guard head 52. Then, if necessary, the guard 50 is somewhatdrawn out, until the key eye 49 registers with one of the threaded holes54 in the guard head 52. The shank 56 of the wing-screw 58 is thenengaged in this hole 54 and the wing-screw tightened to secure the keyto the guard 50.

It will be understood that the downward angulation of the guard head 52,relative to the guard arm 62, and relative to the keyhole slot 74,corresponds to the upward angulation of the key bit 48, in its lockingbolt retaining position, and that the substantially rotationlessengagement of the guard arm 62, in the keyhole 38, precludes rotation ofthe key 42, relative to the lock, and thereby prevents rotation of thekey bit 48, out of the locking bolt retaining position shown in FIGURE3.

The guard Stl serves also to prevent the key 42 from being jarred out ofthe lock '12, when the door D is opened or closed, and slammed.

A .guard 50a, shown in FIGURE 6, is for use where the lock is on theright-hand edge of the door. The guard Sila is the same in constructionas the left-hand guard, shown in FIGURE 5, except that the angulation ofits head 52a, relative to its arm 62a, is the reverse of the head 52 ofthe guard 50, and extends from the opposite side of its arm 62a.

What is claimed is:

I. In combination, a lock case containing an extensible and retractablelocking bolt, said locking bolt being formed with a notch having outerand inner cam edges, the case being formed with a keyhole located in theregion of said notch, a key having a shaft formed with an eye on itsouter end and with a lateral bit at its inner end, the key being engagedthrough the keyhole with its bit positioned in said notch, the key beingadapted to be rotated in opposite directions for operatively engagingthe bit with the cam edges for extending and retracting the lockingbolt, and a guard fixed to the key, said guard having an arm engagednon-rotatably through the keyhole, said keyhole has a vertical slotthrough which the guard arm is non-rotatably engaged, said guardcomprising a relatively wide flat head on the outer end of said arm,said head being angled relative to the guard arm, the bit of the keybeing in upwardly and outwardly angled position relative to the keyholeslot in engagement with the outer cam edge of the bolt notch in theextended position of the bolt and the guard head being in an inwardlyand downwardly angled position relative to the keyhole slot, the bit andthe eye of the key being located in the same plane, the head of theguard and the key eye being angled out of the, horizontal, a side of thehead being engaged with a side of the key eye, and means fixing the keyeye to one side of the guard head.

2. In combination, a lock case containing an extensible and retractablelocking bolt, said locking bolt being formed with a notch having outerand inner cam edges, the case being formed with a keyhole located in theregion of said notch, a key having a shaft formed with an eye on itsouter end and with a lateral bit at its inner end, the key being engagedthrough the keyhole with its bit positioned in said notch, the key beingadapted to be rotated in opposite directions for operatively engagingthe bit with the cam edges for extending and retracting the lockingbolt, and a guard fixed to the key, said guard having an arm engagednon-rotatably through the keyhole, said keyhole has a vertical slotthrough which the guard arm is non-rotatably engaged, said guardcomprising a relatively wide flat head on the outer end of said arm,said head being angled relative to the guard arm, the bit of the keybeing in upwardly and outwardly angled position relative to the keyholeslot in engagement with the outer cam edge of the bolt notch in theextended position of the bolt and the guard head being in an inwardlyand downwardly angled position relative to the keyhole slot, the bit andthe eye of the key being located in the same plane, the head of theguard and the key eye being angled out of the horizontal, a side of thehead being engaged with a side of the key eye, and means fixing the keyeye to one side of the guard head, the guard arm being substantiallynarrower than the guard head and offset to one side edge of the guardhead.

3. In combination, a lock case containing an extensible and retractablelocking bolt, said locking bolt being formed with a notch having outerand inner cam edges, the case being formed with a keyhole located in theregion of said notch, a key having a shaft formed with an eye on itsouter end and with a lateral bit at its inner end, the key being engagedthrough the keyhole with its bit positioned in said notch, the key beingadapted to be rotated in opposite directions for operatively engagingthe bit with the cam edges for extending and retracting the lockingbolt, and a guard fixed to the key, said guard having an arm engagednon-rotatably through the keyhole, said keyhole has a vertical slotthrough which the guard arm is non-rotatably engaged, said guardcomprising a relatively wide fiat head on the outer end of said arm,said head being angled relative to the guard arm, the bit of the keybeing in upwardly and outwardly angled position relative to the keyholeslot in engagement with the outer cam edge of the bolt notch in theextended position of the bolt and the guard head being in an inwardlyand downwardly angled position relative to the keyhole slot, the bit andthe eye of the key being located in the same plane, the head of theguard and the key eye being angled out of the horizontal, a side of thehead being engaged with a side of the key eye, and means fixing the keyeye to one side of the guard head, said means comprising longitudinallyspaced threaded holes in the guard head adapted to be registered withthe opening of the key eye, and a clamping bolt having a shank threadedinto a registered hole and an enlarged diameter head bearing upon thekey eye.

References Cited by the Examiner UNITED STATES PATENTS 30,368 10/1860Wheeler 70-430 567,344 9/1896 Hollingsworth et al. 70-430 1,109,7879/1914 Robinson 70-430 1,235,098 7/1917 Berggren 70-430 1,307,496 6/1919Holcomb 70-429 2,429,913 10/1947 Bald 70-430 EDWARD C. ALLEN, PrimaryExaminer.

P. TEITELBAUM, Assistant Examiner.

1. IN COMBINATION, A LOCK CASE CONTAINING AN EXTENSIBLE AND RETRACTABLELOCKING BOLT, SAID LOCKING BOLT BEING FORMED WITH A NOTCH HAVING OUTERAND INNER CAM EDGES, THE CASE BEING FORMED WITH A KEYHOLE LOCATED IN THEREGION OF SAID NOTCH, A KEY HAVING A SHAFT FORMED WITH AN EYE ON ITSOUTER END AND WITH A LATERAL BIT AT ITS INNER END, THE KEY BEING ENGAGEDTHROUGH THE KEYHOLE WITH ITS BIT POSITIONED IN SAID NOTCH, THE KEY BEINGADAPTED TO BE ROTATED IN OPPOSITE DIRECTIONS FOR OPERATIVELY ENGAGINGTHE BIT WITH THE CAM EDGES FOR EXTENDING AND RETRACTING THE LOCKINGBOLT, AND A GUARD FIXED TO THE KEY, SAID GUARD HAVING AN ARM ENGAGEDNON-ROTATABLY THROUGH THE KEYHOLE, SAID KEYHOLE HAS A VERTICAL SLOTTHROUGH WHICH THE GUARD ARM IS NON-ROTATABLY ENGAGED, SAID GUARDCOMPRISING A RELATIVELY WIDE FLAT HEAD ON THE OUTER END OF SAID ARM,SAID HEAD BEING ANGLED RELATIVE TO THE GUARD ARM, THE BIT OF THE KEYBEING IN UPWARDLY AND OUTWARDLY ANGLED POSITION RELATIVE TO THE KEYHOLESLOT IN ENGAGEMENT WITH THE OUTER CAM EDGE OF THE BOLT NOTCH IN THEEXTENDED POSITION OF THE BOLT AND THE GUARD HEAD BEING IN AN INWARDLYAND DOWNWARDLY ANGLED POSITION RELATIVE TO THE KEYHOLE SLOT, THE BIT ANDTHE EYE OF THE KEY BEING LOCATED IN THE SAME PLANE, THE HEAD OF THEGUARD AND THE KEY EYE BEING ANGLED OUT OF THE HORIZONTAL, A SIDE OF THEHEAD BEING ENGAGED WITH A SIDE OF THE KEY EYE, AND MEANS FIXING THE KEYEYE TO ONE SIDE OF THE GUARD HEAD.